Garage door



Nov. 1, 1955 Filed Feb. 11, 1952 L. S. TAYLOR GARAGE DOOR 2 Sheets-Sheet l INVEN'IOR. LLOYD S. TAYLOR BY t ATTOQ/ EY Nov. 1, 1955 L. s. TAYLOR 2,722,273

GARAGE DOOR Filed Feb. 11, 1952 2 Sheets-Sheet 2 INVENTOR. M LLOYD s. TAYLOR A TTOPME) United States Patent C GARAGE DOOR Lloyd S. Taylor, Atlanta, Ga. Application February 11, 1952, Serial No. 271,009

6 Claims. (Cl. 160191) My invention relates to folding doors, and more particularly to a garage door which may be folded into the roof section of a garage or other similar structure.

This application is a continuation-in-part of my copending application, Serial No. 115,126, filed September 12, 1949, now abandoned, entitled Garage Door.

In the past, many types of doors have been marketed incorporating the idea of folding or sliding the door sections up into the top section of a garage, thus opening the door. These doors have with them certain counterbalance features such as a weight connected through a cable to the bottom section of the door; however, no prior device incorporates a counterbalance completely integral with the door section itself. In the prior art devices, it is necessary, in assembling the door on a garage or other structure, to anchor a certain portion, either the spring or the end of the cable of the counterbalance system, to the supporting structure. This operation is time consuming and prevents the prefabrication of the door together with final adjustment of the counterbalance system at a factory or place of assembly of the door. Therefore, in the prior art devices, it is necessary after a door has been installed on a building or structure to attempt to adjust the spring mechanism manually.

In the prior art devices mentioned above, it has been proposed to so design the drum and spring assembly associated with the door that the tension on the cable increases as the door is opened. I have found however that by incorporating a drum and spring assembly which will maintain a constant tension on the cable, the weight of a door constructed in accordance with my invention, may be counterbalanced at all positions and that no chain hoist or other braking mechanism is necessary. This requires however careful calculation in advance and only with a particular preloading of a particular spring of a given constant in combination with a drum having a particular taper will the door be operable in this way.

In all prior art devices three important things were missing: First, there was no Way of installing counterbalancing mechanism at the factory so that this particular preloading could be given the spring. In the prior art devices, it was left to chance that after installation of the door, a proper preloading would be given the counterbalance assembly and usually entrusted to the installer who did not know what preloading was necessary.

Secondly, it was not appreciated in the prior art that a spiral drum and spring assembly having certain characteristics would provide an automatic brake as the door approached the top. Therefore, when attempts were made to construct a drum and spring assembly, they were constructed to provide increased tension as the door approached the top or open position.

Thirdly, no prior art doors are So completely counterbalanced that the door will remain in any position in which it is stopped.

Accordingly, it is an object of my invention to provide a door consisting of an upper and a lower panel, hinged together at their abutting horizontal joint, and provided 2,722,273 Patented Nov. 1, 1955 with a counterbalance system completely integral therewith.

Another object of my invention is to provide a folding door which is easily prefabricated and quickly and inexw pensively installed within a structure or building.

Another object of my invention is to provide a folding doorwhich is counterbalanced by a constant force throughout its entire travel in being opened and closed, thus providing a door which may be opened or closed with a minimum of effort.

Another object of my invention is to provide a door which folds into the overhead section of the supporting structure which door will not stick or wedge in the open position.

Another object of my invention is to provide a folding door which requires a minimum of vertical clearance between the lintel and inside roof structure.

Another object of my invention is to provide a folding door which will stop gently as it approaches the open position.

Another object of my invention is to provide a door which is inexpensive to manufacture, durable in construction, and efficient in operation.

Other and further objects and advantages of my invention will become apparent from the following description when taken in conjunction with the accompanying drawings in which like characters of reference designate corresponding parts throughout the several views, and wherein:

Fig. l is a partially broken inside elevation of a door constructed in accordance with my invention and mounted for use.

Fig. 2 is a side view of the door illustrated in Fig. 1, showing in broken lines the door partially open.

Fig. 3 is a side view similar to Fig. 1, but with the door completely raised.

Fig. 4 is a view of a detail showing the arrangement of the lower corner of the door illustrated in Fig. 1.

Fig. 5 is an enlarged view of a detail.

d Fig. 6 is a vector diagram of the forces acting on the oor.

Fig. 7 is a side elevation of an optional arrangementof the drums, spring and cable.

Fig. 8 is a fragmentary view of the door shown in Fig. 1 showing the lock arrangement.

Fig. 9 is an enlarged view of a detail.

Referring now in detail to the embodiment chosen for purpose of illustration, the door itself is shown as comprising an upper panel 10 positioned above a lower panel Y11 and hinged thereto by piano hinge 12 affixed between the horizontal abutting edges of the panels, thus allowing the panels to fold as shown by broken lines in Fig. 2. Therefore, when the door is closed, the panels are vertically positioned one above the other, as described above; and, as the door is opened, the faces of these panels come together as both panels fold and approach a horizontal position as shown in Fig. 3.

Upright trackways or jambs 13, 13' positioned adjacent the sides of the door, as shown in Fig. l, and fixed to the supporting structure, support the door which is pivotally mounted therebetween by shafts 14, 14 respectively retained in sleeves 15, 15' which in turn are respectively fixed to the upper corners of the upper panel 10. Bearings 16, 16 are respectively mounted at the top of jambs 13, 13 and pivotally retain shafts 14, 14. Lock screws 17, 17 threadably extend respectively into sleeves 15, 15' and respectively engage shafts 14, 14'.

On the bottom corners of lower panel 11 are mounted respectively rollers 18, 18' which ride against the inward flaring section of jambs 13, 13' respectively. As shown in Fig. 1, flanges 19, 19' respectively extend along the lower section of jambs 13, 13' to partially encompass the adjacent rollers and prevent swinging of the door when it is closed.

From the above description, it will be obvious that upon opening the door, the upper and lower panels will jackknife, the hinged edges moving inwardly, as upper panel pivots about shafts 14, 14 and the lower corners of the lower panel 11 are retained in a plane with jambs 13, 13'.

Since the above described movement of the panels involves considerable work, due to the weight of the parts, I have provided a counterbalance consisting of a horizontal spring shaft journaled within spaced brackets 21, 21' on the inner face of upper panel 10, adjacent but below shafts 14, 14', with truncated substantially coneshaped drums 22, 22' aflixed respectively to the ends of shaft 20, as shown in Fig. 1. Drums 22, 22 have helical grooves around their peripheries and cables 23, 23' respectively fixed by their ends to the largest diameter section thereof with the other ends of cables 23, 23' respectively affixed to lifting fingers 24, 24- on the lower section of lower panel 11. A helical spring 25 is wound around shaft 20 substantially throughout its entire length, being fixed to bracket 21 and shaft 20 to provide spring tension for drums 22, 22, urging them in a direction to wind cables 23, 23' in the grooves thereon.

It should be remembered that the force exerted by spring 25 is proportional to the angular displacement of shaft 20, within the elastic limits of the spring. Also, the force exerted by cables 23, 23 is inversely proportional to their lever arms or the radii of drums 22, 22 at that position. Therefore, it will be apparent that by varyingthe diameter of drums 22, 22' as described above, a pull of constant force may be imparted to cables 23, 23 or a pull which varies with the length of cable unwound from drums 22, 22' may be imparted, all being dependent upon the diameter of the drum at the specific point at which the cable leaves the drum.

It should be noted that the rollers 18, 18' make the effective length of upper panel 10 slightly less than lower panel 11; thus insuring that the rollers 18, 18 will never travel past the point at which the rollers will be urged up by the weight of the door instead of down as is shown. Figs. 8 and 9 illustrate the locking means incorporated with lower panel 11 which comprises pivoted locking tabs 26, 26' extending respectively from the sides of lower panel 11 and engaging flanges 19, 19. Cables 27, 27' extend respectively from tabs 26, 26' over rollers 28, 28' and join at lever 29 which is attached to lock 30. Fig. 9 shows a spring 31 urging tab 26 into a locked position.

The section of cables 27, 27 between rollers 28, 28 and lever 29 provide a handle for opening the door. By merely pulling upon this section of the cables, the locking tabs are actuated against the pressure of the respective springs 31 to clear the flanges 19. Of course, tabs 26, 26' may also be actuated by an outside handle (not shown) which is incorporated with lock to rotate lever 29.

Referring to Fig. 6, it may be shown through vector analysis that the force necessary to counterbalance my door may be expressed as:

W, Cos 9 Sin 0 Pl; 2 Sin 20 2 where Wt is the total weight of the door and W1 is the weight of the lower panel 11, of the door. Substituting in this formula indicates that as the door is lifted, the force necessary to counterbalance the door remains substantially constant throughout approximately all of its travel.

With a door weighing 64 pounds having a 3 pound spring assembly, a 35 pound pull or tension is necessary to counterbalance the door. In designing a spring and drum, I have found suitable drums 22, 22 having 6 inch diameters which taper to 3 inch diameters and being provided with grooves, as described above, which will accommodate about 6 feet of a 7 foot cable. Spring 25 may be inch diameter wire having turns, 26 inches long and having an inside diameter of 1.412 inches. When this assembly is mounted on the door, approximately 9 turns of preloading is necessary to adjust the cable tension to approximately 35 pounds. It should be remembered that while I have illustrated but one weight door, my invention is not restricted to that one weight.

Also, when designing a door of any weight or size which is constructed in accordance with my invention, it is only necessary to solve the foregoing equation for the counterbalancing force by using substantially any angle more than about 10 degrees. Then use this force to determine the size spring and drums to be selected. Many factors may enter into the selection of the proper size drums such as the number of coils of wire in a given spring and its elastic limits or the clearance between the lintel and inside roof structure. Generally speaking, however, the size drums mentioned above will be sufficient for any average weight door and it is only necessary to provide a spring which is suitable, the characteristics and preloading of the spring being such that the force exerted by the spring will double as the diameter of the tapered drums at the point of departure of the cable becomes one-half the larger diameter. The formulae to calculate the size spring to be used are readily available and therefore not included here.

It will be seen that my improved door may be shipped as a preassembled unit and affixed in place by merely inserting shafts 14, 14' in their bearings 16, 16' after jambs 13, 13' have been installed.

Shaft 20 may be located at any point on either panel provided the lift cables pass over rollers near the edges of that section opposite the hinged abutting edges of the panels and are attached to lifting fingers at corresponding points on the other section. This arrangement is shown in Fig. 7 in which the lift shaft is shown mounted on an intermedaite portion of the upper panel and the lift cables as passing over pulleys near the free edges of that panel and connected to fingers 24, 24' near the free edge of the lower panel.

It will be obvious to those skilled in the art that my invention provides a needed article of great convenience and usefulness for which many adaptations and uses will be found, and that while I have illustrated and described my invention in a very practical embodiment thereof without attempting ot illustrate or describe other embodiments, various changes may be made without departing from the scope of my invention as defined in the appended claims.

I claim:

1. A self-contained door unit including a plurality of movable panels hinged together at their abutting edges,

pivots for one of said panels and about which it may swing located adjacent the edge of one of said panels remote from the hinged connection, a device mounted on one of said panels and movable with the same including a rotatable shaft, bearings for said shaft carried by one of said door panels, a loaded power spring surrounding said shaft and having one end affixed to the door panel and the opposite end affixed to said shaft, helically grooved conical drums carried adjacent opposite ends of said shaft, a cable individual to each drum having one end arranged to be wound in said helical grooves and having its opposite end attached to another of said panels, said helically grooved conical drum and said spring being so constructed and arranged as to elfectively counterbalance said door unit in all positions of the panels and maintain substantially constant tension upon each said cable.

2. A self-contained door unit including an upper panel and a lower panel having their abutting edges hinged together, stationary pivots for the upper panel and about which it may swing located adjacent the edge of said panel remote from the hinge connection, a counterbalancing device including a plurality of conical drums having helical grooves therein of predetermined radius, a shaft connected to said drums extending across said upper panel, a spring loaded to a predetermined tension surrounding said shaft and having one end fixed to said panel and the opposite end fixed to said shaft to maintain the predetermined energy of said spring, means for supporting said counterbalancing device on said upper panel intermediate said pivots and the hinge connection, and a cable individual to each drum and passing over the same and having its free end connected to said lower panel, the characteristics and loading of said spring being such that the force exerted by said spring will double as the diameter of said drums at the point of departure of said cable therefrom becomes one-half the larger diameter.

3. A door unit including a plurality of panels having abutting edges hinged together, stationary pivots for one of said panels and about which it may swing located adjacent the edge of one of said panels remote from the hinged connection, a counterbalancing device including a plurality of conical drums having helical grooves therein of predetermined radius, a shaft connected to said drums extending across said panel, a spring of predetermined tension surrounding said shaft having one end permanently fixed to the door panel and the opposite end permanently fixed to said shaft, means for supporting said counterbalancing device on said panel intermediate said pivots and the hinged connection, a cable individual to each drum and passing over the same and having its free end connected to the other of said panels, straight line trackways for said door, and guiding devices carried by said other panel adjacent its edges remote from the hinge connection traveling in said trackways, the characteristics and loading of said spring being such that the force exerted by said spring doubles as the diameter of said drums at the point of departure of said cable therefrom becomes one-half the larger diameter.

4. A self-contained door unit including a plurality of door panels hinged together at their abutting edges, pivots for one of said panels and about which it may swing located adjacent the edge of one of said panels remote from the hinged connection, a device mounted on the interior face of one of said panels and movable with the same including a rotatable shaft, power means for rotating said shaft, conical drums provided with helical grooves carried adjacent the outer ends of said shaft, a cable individual to each drum having one end arranged to be wound in said helical grooves and having its opposite end attached to another of said panels, said power means and conical drums being so constructed and arranged as to effectively counterbalance said door unit in all positions of the panels and maintain substantially constant tension upon each said cable.

5. A door unit including a plurality of door panels hinged together at their abutting edges, pivots for one of said panels and about which it may swing located adjacent the edge of one of said panels remote from the hinged connection, a device mounted on the interior face of one of said panels and movable with the same including a rotatable shaft, power means for rotating said shaft, conical drums provided with helical grooves carried adjacent the outer ends of said shaft, a cable individual to each drum having one end arranged to be wound in said helical grooves and having its opposite end attached to another of said panels, said power means and conical drums being so constructed and arranged as to effectively counterbalance said door unit in all positions of the panels and maintain substantially constant tension upon each said cable, straight line trackways for said door, and guiding devices carried by the free end of said other panel traveling in said trackways.

6. A door comprising an upper panel, a lower panel below said upper panel, a hinge connecting said lower panel to said upper panel, jambs on a supporting structure, said upper panel being pivotally mounted to the upper section of said jambs, rollers extending from said lower panel and engaging said jambs, a shaft mounted horizontally for rotation on said upper panel, a spring fixed to said upper panel and said shaft, a helically grooved tapered drum having a large and small diameter fixed to said shaft, a cable connecting said lower panel and the large diameter section of said drum, said spring urging said drum to wind said cable in said helical groove when said door is opened, said spring and said drum being proportioned so that the force exerted by said cable is substantially constant throughout the travel of said cable in said groove, pivot tabs on said lower panel engaging said jambs to lock said door in closed position, and actuating cables connected to said pivot tabs for unlocking and opening said door.

References Cited in the file of this patent UNITED STATES PATENTS 924,686 McCloud June 15, 1909 1,629,973 Rush et al. May 24, 1927 1,721,501 McKee July 23, 1929 1,994,785 Premo Mar. 19, 1935 2,338,205 Rowe Jan. 4, 1944 

